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    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
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    <title>Document</title>
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<body>
    <script>
        // 编写一个函数 ，输入一个数字，返还数字的长度

function sum(a){
 
        var a='54844626';
        console.log(a.length);
        return a;
}


sum(0);



    </script>
</body>
</html>